Product Description

Product Introduction: 309S and 309H Alloys – High-Performance Solutions for Elevated Temperatures

Introducing the 309S and 309H alloys, known under UNS designations S30908 and S30909 respectively. These alloys are engineered for applications requiring outstanding strength and corrosion resistance in high-temperature environments. With their unique combination of chromium and nickel, they are ideal choices for industries such as aerospace, chemical processing, and energy production.

Physical Properties Overview

In the annealed condition, both 309S and 309H exhibit remarkable physical properties across a temperature spectrum from -20°F to +100°F. Both alloys possess a tensile strength of approximately 75,000 psi (515 MPa) and a yield strength of 30,000 psi (205 MPa). One of the standout features of these alloys is their elongation percentage, measuring a minimum of 35% in a 2-inch length, which indicates excellent ductility necessary for fabrication and forming.

The maximum hardness of 90 Rb ensures that both alloys maintain a balance between strength and workability. Moreover, the modulus of elasticity is consistently recorded at about 29.0 x 10^6 psi, affirming the rigidity of these alloys under stress. The mean coefficient of thermal expansion is measured at 9.2 x 10^-6 in/in/°F, making them suitable for operations involving significant temperature fluctuations.

Chemical Composition

The composition of these alloys significantly contributes to their performance. The 309S alloy features chromium content ranging between 22.0% and 24.0% and nickel between 12.0% and 15.0%. The 309H alloy shares similar chromium levels but allows for a slightly varied carbon content, enabling enhanced high-temperature strength. The controlled addition of elements such as manganese, silicon, phosphorous, and sulfur ensures a reliable material structure while maintaining a maximum carbon level of 0.08% for 309S and up to 0.10% for 309H.

Applications in Industry

The versatility of 309S and 309H alloys is emphasized in numerous high-temperature applications. These alloys excel in fabricating components for industrial furnaces, heat exchangers, and pressure vessels. Their outstanding oxidation resistance makes them essential for applications in the petrochemical industry, including reactors and piping systems that operate under severe conditions.

309S is frequently used in situations where welding is required due to its good weldability, allowing manufacturers to create complex shapes and designs without compromising performance. Meanwhile, 309H is recognized for its superior properties in high-stress scenarios, making it suitable for power generation components such as boiler tubes and high-temperature gas turbine engines.

Conclusion

In summary, the 309S and 309H alloys represent some of the best materials suited for environments where temperature and corrosion resistance are paramount. Their superior mechanical properties, coupled with their versatile applications in various industries, make them essential materials for engineers and manufacturers looking to optimize performance and durability.

When selecting alloys for critical applications, it is advisable to consult with industry experts to ensure that 309S or 309H alloys will meet the specific requirements and standards of the intended use. With their reliability and strength, these alloys continue to play a crucial role in advancing industrial technologies while upholding safety and efficiency. Whether for new projects or repairs, 309S and 309H alloys should be inherently considered in high-performance material selections.